A 13.8 ft storm surge flooded nearly 75 percent of the island when Superstorm Sandy passed through New York Harbor. Liberty Island’s 50,000 sq ft brick paver promenade was destroyed by the storm and had to be rebuilt. National Park Service
The Statue of Liberty National Monument, and the 12-acre island that houses it, have reopened to the public once again.
July 16, 2013—The Statue of Liberty is one of the most recognizable monuments in the United States—a symbol of freedom to the millions of immigrants who have arrived since its erection in 1886 and a beloved icon of New York City. Earlier this month, on the Fourth of July, the statue reopened following a 20-month closure that was punctuated by one open day: October 28, 2012, the day immediately preceding the arrival of Superstorm Sandy. Prior to the storm, the interior of the statue’s pedestal was rebuilt to become code-compliant in an approximately $30-million project to meet current life and safety codes. After nearly 75 percent of the island was flooded in Sandy’s storm surge, the National Park Service spent an additional $7.6 million to repair the damage caused to the island itself.
The 151 ft tall statue is formed of copper sheeting measuring a mere 3/32 in. (the thickness of two pennies placed together) that is riveted to armature bars, which then connect to a 92 ft tall steel pylon. Created by Alexandre-Gustave Eiffel—who later designed Paris’s Eiffel Tower—the system acts as a skeletal support and curtain wall system that enables the statue to react to thermal shifts and sway in the wind, according to the National Park Service’s website. In winds of 50 mph, the statue is known to sway up to 3 in., and the torch up to 6 in. The statue is situated within the star-shaped walls of historic Fort Wood, on a 154 ft tall concrete pedestal that is fronted with granite blocks.
The six-level interior of the statue’s pedestal was completely gutted in the life and safety work completed prior to Sandy’s arrival. “We demolished all of the structural steel and basically brought that pedestal to four concrete perimeter walls and the Eiffel structure,” says Paul Natoli, the president and chief executive officer of Pine Brook, New Jersey-based Joseph A. Natoli Construction Corporation and the project executive for the company’s work on Liberty Island. “The Eiffel structure is really a series of major massive beams at different elevations that hold up the Statue—it’s an engineering marvel—[and] we were not allowed to use those beams for any support.”
Rebuilding the interior elements of the pedestal included creating two new, wider, code-compliant stairways; a main elevator that would rise from the lowest level of the pedestal to its fifth floor; and a wheelchair lift that would transport visitors from that fifth-floor elevator’s terminus to the sixth-floor exterior observation deck. A replacement emergency elevator was installed from the sixth floor level of the pedestal to the shoulder height of the statue. All of the new work had to wind around two sets of four girders that tie the statue to the pedestal, a set of 4 ft deep girders at the statue’s base, and a second set of 3 ft deep girders at the midway point of the pedestal.
Two new, wider, code compliant stairways; a main elevator that
rises from the lowest level of the pedestal to the fifth floor; and a
wheelchair lift that transports visitors between the fifth and sixth
floors to access the exterior observation deck were added during
the life and safety work performed on the interior of the pedestal.
National Park Service
“Weaving two separate stair structures and an elevator hoistway through that space required finesse,” wrote Denise L. Richards, P.E., an associate of Philadelphia-based Keast & Hood Co., the structural engineers for the renovation, in response to written questions posed by Civil Engineering online. “It was a little like making a delicate piece of jewelry out of steel and concrete.”
The stairs utilize structural steel spanning between the interior concrete walls of the pedestal with cast-in-place concrete on the treads, risers, and landings, according to Richards. “The elevator shaft and related walls were done in cast-in-place concrete for a variety of reasons, including its strength and durability,” she said. Using cast-in-place concrete for the elevator “enabled the walls to be thin while maintaining the needed strength for load bearing,” she said. “Concrete enabled us to shape and construct the walls to suit the fine tolerances of the space, and the material is visually compatible with the historical, exposed concrete of the interior of the pedestal.” Chemical anchors were used to tie the new structures into the pedestal walls to minimize the impact on the historical fabric.
Considering the tight spaces and small tolerances, the use of building information modeling was crucial to the success of the project, according to Richards.
However, despite the careful planning implemented by the design team, it also had to be ready to adjust its plans at any given moment because original drawings were not available, according to Thomas J. Normile, P.E., a principal of Keast & Hood, who wrote in response to written questions submitted by Civil Engineering online.
Within the pedestal the new stairs (indicated in orange) had to
avoid two sets of four girders that tie the statue to the pedestal,
a set of 3 ft deep girders (indicated in green) at the midway point
of the pedestal, and a set of 4 ft deep girders at the statue’s
base. Rendering © Keast & Hood Co.
The construction team led by Natoli managed the interior work by leaving the original sixth level in place during construction so that it could be used to hoist material. “When we got to that level, then we brought in our demolition crews and our dismantling crews again, and we dismantled that, so that all we had to do was to work vertically without any structure for the last, say, 20 feet, as opposed to trying to do that for a 130 feet,” Natoli says.
Despite the grand opening of the statue in October 2012, a number of small items still needed to be completed on the project. Those were put on hold when Superstorm Sandy arrived, with its 13.8 ft storm surge. “It was Armageddon there,” Natoli says. “The damage that had occurred, not to the Monument, but rather to the island itself, was unbelievable. The docks were destroyed, all of the main arteries to the island, the electrical power, the domestic water pumps, the sanitary and storm systems, [all] were destroyed.”
According to Natoli, every building on the island had a flooded basement and between 3 and 4 ft of water in its first floor. To protect the island from future storms and flooding, all electrical switches and major infrastructure equipment have been relocated from basements to a central mechanical and electrical building—housed in the former incinerator building—that contains a new steel floor located 14 ft above ground level.
Superstorm Sandy destroyed the docks at the 12-acre Liberty
Island, home to the State of Liberty. The destruction of the docks
complicated work on the island so a 70 ft amphibious boat capable
of beach landings was used to transport construction supplies.
National Park Service
In addition to replacing the electrical, fuel, water, storm, and sanitary systems in their entirety, Natoli’s team also replaced the promenade on which visitors walk throughout the island; the promenade had been wiped out by the storm. “The brick pavers came up like potato chips, and just were piled here and there and everywhere,” Natoli says. “That was a huge challenge for us—it was over 50,000 square feet of brick pavers that needed to be demolished, and the subsurface repaired and the pavers then reinstalled.”
With the destruction of the docks in the storm, Natoli’s ability to complete the final elements of his team’s work on the pedestal project and its storm repair work became impossible—until his team located a 70 ft amphibious boat capable of beach landings. His team shuttled everything needed to and from the site to complete their work on the pedestal project and repair the storm’s damage via the small beach located on the island.
The Statue of Liberty has been a nationally protected monument since 1924, 38 years after its original dedication; in 1937 the designation was expanded to include the entire island, according to the United Nation’s World Heritage website. The Statue of Liberty was dedicated as a U.S. National Monument in 1965, was listed in the National Register of Historic Places in 1966, and was recognized by ASCE as a Historic Civil Engineering Landmark in 1985.